Optimizing Adaptive Disturbance in Planted Forests: Resource Allocation Strategies for Sustainable Regeneration From Seedlings to Saplings

ABSTRACT Climate change intensifies regeneration bottlenecks in plantations via increased drought and phenological shifts, particularly in water‐limited temperate ecosystems. As a globally significant afforestation model, China's Three‐North Shelterbelt Program exemplifies regeneration challenges in monoculture plantations across temperate ecotones, where successful regeneration depends on precise management timing. Within this context, we investigated Larix principis‐rupprechtii regeneration under three thinning intensities (~25%, ~45%, ~65%) across post‐thinning recovery stages (short‐term: < 3 yr; medium‐term: 3–6 yr; long‐term: > 6 yr) to develop time‐specific regeneration protocols. Moderate thinning (~45%) maximized seedling density (8583 trees hm⁻ 2 ) during the medium‐term stage. A strategic seedling shifts from shade avoidance (high height‐to‐diameter ratio, HDR) to shade tolerance (low HDR) occurred at ~3 years post‐thinning, enhancing radial growth. Thinning triggered cascading resource effects: increased light availability accelerated litter decomposition (path coefficient = 0.75), subsequently improving soil moisture‐nutrient conditions and enzyme activity (0.61). Key regeneration drivers shifted temporally: plant architectural traits dominated short‐term regeneration (45.8% variance explained), neighborhood biotic interactions prevailing in the medium term (59.8%), and abiotic factors controlled long‐term outcomes (52.6%). These findings provide critical technical guidance for establishing climate‐resilient regeneration frameworks in temperate plantations.